Fallopia japonica (Japanese knotweed) is an aggressively invasive herbaceous perennial
that causes substantial economic and environmental damage in the United
Kingdom (UK). As such, it is of considerable concern to councils, environmental
groups, private landowners and property developers. We construct a 3D correlated
random walk model of the development of the subterranean rhizome network for a
single stand of F. japonica. The formulation of this model uses detailed knowledge
of the morphology and physiology of the plant, both of which differ in the UK to
that of its native habitat due to factors including a lack of predation and competition,
longer growth seasons and favourable environmental conditions in the UK.
Field data obtained as a part of this study are discussed and used in the model for
parameterisation and validation. The simulation captures the field data well and predicts, for example, quadratic growth in time for the stand area. Furthermore,
the role of a selection of parameters on long-term stand development are discussed,
highlighting some key factors affecting vegetative spread rates.